引出做某事的人或东西，或介绍做某事的方法。
"By" introduces what (or how) something is done by or the method by which it is done.
有时候，说明如何做某事的最好方法是举反例。
Sometimes the best way to illustrate how to do something is by counterexample.
要说明你做某事的次数，你可以用几种表达方法。
To talk about how many times you have done something, you can say various things, e.g.
假设你想训练某人做某事，你想要找到一种训练方法，使得他们即便不再接受训练，也依然能够持续展现某种行为，而这正是你想要的。
Suppose you want to train somebody to do something and you want the training such that they'll keep on doing it even if you're not training them anymore, which is typically what you want.
这是做某事……的方法。
结构用来表达做某事的最好方法是…
结构用来表达做某事的最好方法是…
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